Positive electrode for nonaqueous secondary battery, method for forming the same, nonaqueous secondary battery, and electrical device

Abstract

A positive electrode for a nonaqueous secondary battery including an active material layer which has sufficient electron conductivity with a low ratio of a conductive additive is provided. A positive electrode for a nonaqueous secondary battery including an active material layer which is highly filled with an active material, id est, including the active material and a low ratio of a conductive additive. The active material layer includes a plurality of particles of an active material with a layered rock salt structure, graphene that is in surface contact with the plurality of particles of the active material, and a binder.

What is claimed is: 
     
         1 . A lithium-ion secondary battery comprising:
 a positive electrode comprising a positive electrode active material layer;   a negative electrode; and   an electrolyte,   wherein the positive electrode active material layer comprises:
 a plurality of multi-layer graphene; 
 an active material comprising a plurality of active material particles represented by a general formula LiNi x Mn y Co 1-x-y O 2 , x being larger than 0, y being larger than 0, x+y being smaller than 1; and 
 a binder, 
   wherein one of the plurality of the multi-layer graphene is in surface contact with one of the plurality of the active material particles, and   wherein the one of the plurality of the multi-layer graphene is in surface contact with the other one of the plurality of the multi-layer graphene.   
     
     
         2 . The lithium-ion secondary battery according to  claim 1 , wherein the electrolyte comprises ethylene carbonate. 
     
     
         3 . The lithium-ion secondary battery according to  claim 1 , wherein the electrolyte comprises ethylene carbonate and diethyl carbonate. 
     
     
         4 . The lithium-ion secondary battery according to  claim 1 , wherein the negative electrode comprises graphite. 
     
     
         5 . The lithium-ion secondary battery according to  claim 1 , wherein a weight ratio of the active material to the positive electrode active material layer is higher than or equal to 84.2 wt % and lower than or equal to 98.9 wt %. 
     
     
         6 . The lithium-ion secondary battery according to  claim 1 , a weight ratio of the plurality of the multi-layer graphene to the positive electrode active material layer is higher than or equal to 0.05 wt % and lower than or equal to 5.3 wt %. 
     
     
         7 . An electric vehicle comprising:
 the lithium-ion secondary battery according to  claim 1 ; and   a drive motor unit.   
     
     
         8 . A lithium-ion secondary battery comprising:
 a positive electrode comprising a positive electrode active material layer;   a negative electrode; and   an electrolyte,   wherein the positive electrode active material layer comprises:
 a plurality of multi-layer graphene; 
 an active material comprising a plurality of active material particles represented by a general formula LiNi x Mn y Co 1-x-y O 2 , x being larger than 0, y being larger than 0, x+y being smaller than 1; and 
 a binder, 
   wherein the plurality of the active material particles comprises a first plurality of active material particles which has small particle diameter and a second plurality of active material particles which has large particle diameter,   wherein one of the plurality of the multi-layer graphene is in surface contact with one of the plurality of the active material particles, and   wherein the one of the plurality of the multi-layer graphene is in surface contact with the other one of the plurality of the multi-layer graphene.   
     
     
         9 . The lithium-ion secondary battery according to  claim 8 , wherein the electrolyte comprises ethylene carbonate. 
     
     
         10 . The lithium-ion secondary battery according to  claim 8 , wherein the electrolyte comprises ethylene carbonate and diethyl carbonate. 
     
     
         11 . The lithium-ion secondary battery according to  claim 8 , wherein the negative electrode comprises graphite. 
     
     
         12 . The lithium-ion secondary battery according to  claim 8 , wherein a weight ratio of the active material to the positive electrode active material layer is higher than or equal to 84.2 wt % and lower than or equal to 98.9 wt %. 
     
     
         13 . The lithium-ion secondary battery according to  claim 8 , a weight ratio of the plurality of the multi-layer graphene to the positive electrode active material layer is higher than or equal to 0.05 wt % and lower than or equal to 5.3 wt %. 
     
     
         14 . An electric vehicle comprising:
 the lithium-ion secondary battery according to  claim 8 ; and   a drive motor unit.